Magnetic Field and Lenz's Law Inversion?
A superconducting material, when cooled, exhibits perfect diamagnetism. You are given a long solenoid with its axis aligned with the radius of a superconducting ring. When the current in the solenoid is switched on, devise a method to induce a current in the superconducting ring using the principle of electromagnetic induction.
1 Answer
📌 CONCEPT: Electromagnetic induction is the production of an electromotive force (EMF) across an electric conductor in a changing magnetic field.
📐 RULE / FORMULA: Lenz's Law states that the direction of the induced current is such that it opposes the change in the magnetic field that caused it.
💡 WORKED EXAMPLE: The given setup can be used to induce a current in the superconducting ring by first creating a changing magnetic field around it by switching on the current in the solenoid. The current induced in the superconducting ring will then flow in a direction that opposes this change in the magnetic field. By carefully measuring the direction of the induced current, we can determine the direction of the changing magnetic field.
⚠️ COMMON MISTAKE: Students often get confused between Lenz's Law and Faraday's Law of induction, which describe different aspects of electromagnetic induction.
24 Oct 26
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